Medical leads provide electrical stimulation from a medical device to a target site within a body of a patient. The medical device is typically implanted or otherwise installed on the body in an accessible area at some distance from the target site, and the medical lead is routed to the target site either through a percutaneous procedure or by surgical implantation depending upon the type and size of the medical lead being implanted.
Because the medical lead extends some distance between the medical device and the target site within the body, the medical lead is subject to forces imposed by movements of the patient. In particular, the medical lead may be subjected to strain. To address the strain, the medical lead may be routed by creating a loop that relieves the strain by the loop making available an additional length of the lead.
An additional benefit of the strain relief loop occurs in relation to radiofrequency (RF) heating at the electrodes. RF heating can occur when the patient is exposed to relatively high levels of RF energy such as during a magnetic resonance imaging (MRI) scan. The metal conductors within the lead such as filars connected to the electrodes have current induced by the RF energy. This induced current can produce heating within the medical lead and at the electrodes. The presence of the strain relief loop, particularly if the loop is created in relatively close proximity to the distal end of the medical lead where the electrodes are located, reduces such heating which improves the comfort of the patient and lessens the risk of injury during MRI scans.
An issue is that strain relief loops may be considered optional and/or may be overlooked by some clinicians and therefore are not necessarily created in all instances. Thus, one implantation of a given medical system that includes a strain relief loop may offer better protection for the patient from RF heating than a same medical system that is implanted in a patient without a strain relief loop.